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5131 | clevermous | 1 | /* |
2 | IMGLIB: An example image loading library for use with SDL |
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3 | Copyright (C) 1999 Sam Lantinga |
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4 | |||
5 | This library is free software; you can redistribute it and/or |
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6 | modify it under the terms of the GNU Library General Public |
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7 | License as published by the Free Software Foundation; either |
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8 | version 2 of the License, or (at your option) any later version. |
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9 | |||
10 | This library is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 | Library General Public License for more details. |
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14 | |||
15 | You should have received a copy of the GNU Library General Public |
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16 | License along with this library; if not, write to the Free |
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17 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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18 | |||
19 | Sam Lantinga |
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20 | 5635-34 Springhouse Dr. |
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21 | Pleasanton, CA 94588 (USA) |
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22 | slouken@devolution.com |
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23 | */ |
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24 | |||
25 | /* |
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26 | * PNM (portable anymap) image loader: |
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27 | * |
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28 | * Supports: PBM, PGM and PPM, ASCII and binary formats |
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29 | * (PBM and PGM are loaded as 8bpp surfaces) |
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30 | * Does not support: maximum component value > 255 |
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31 | */ |
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32 | |||
33 | #include |
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34 | #include |
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35 | #include |
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36 | #include |
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37 | |||
38 | #include "SDL_image.h" |
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39 | |||
40 | #ifdef LOAD_PNM |
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41 | |||
42 | /* See if an image is contained in a data source */ |
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43 | int IMG_isPNM(SDL_RWops *src) |
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44 | { |
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45 | char magic[2]; |
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46 | |||
47 | /* |
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48 | * PNM magic signatures: |
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49 | * P1 PBM, ascii format |
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50 | * P2 PGM, ascii format |
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51 | * P3 PPM, ascii format |
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52 | * P4 PBM, binary format |
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53 | * P5 PGM, binary format |
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54 | * P6 PPM, binary format |
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55 | */ |
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56 | return (SDL_RWread(src, magic, 2, 1) |
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57 | && magic[0] == 'P' && magic[1] >= '1' && magic[1] <= '6'); |
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58 | } |
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59 | |||
60 | /* read a non-negative integer from the source. return -1 upon error */ |
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61 | static int ReadNumber(SDL_RWops *src) |
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62 | { |
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63 | int number; |
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64 | unsigned char ch; |
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65 | |||
66 | /* Initialize return value */ |
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67 | number = 0; |
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68 | |||
69 | /* Skip leading whitespace */ |
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70 | do { |
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71 | if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
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72 | return(0); |
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73 | } |
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74 | /* Eat comments as whitespace */ |
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75 | if ( ch == '#' ) { /* Comment is '#' to end of line */ |
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76 | do { |
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77 | if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
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78 | return -1; |
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79 | } |
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80 | } while ( (ch != '\r') && (ch != '\n') ); |
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81 | } |
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82 | } while ( isspace(ch) ); |
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83 | |||
84 | /* Add up the number */ |
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85 | do { |
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86 | number *= 10; |
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87 | number += ch-'0'; |
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88 | |||
89 | if ( !SDL_RWread(src, &ch, 1, 1) ) { |
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90 | return -1; |
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91 | } |
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92 | } while ( isdigit(ch) ); |
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93 | |||
94 | return(number); |
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95 | } |
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96 | |||
97 | SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
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98 | { |
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99 | SDL_Surface *surface = NULL; |
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100 | int width, height; |
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101 | int maxval, y, bpl; |
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102 | Uint8 *row; |
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103 | Uint8 *buf = NULL; |
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104 | char *error = NULL; |
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105 | Uint8 magic[2]; |
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106 | int ascii; |
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107 | enum { PBM, PGM, PPM } kind; |
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108 | |||
109 | #define ERROR(s) do { error = (s); goto done; } while(0) |
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110 | |||
111 | if(!src) |
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112 | return NULL; |
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113 | |||
114 | SDL_RWread(src, magic, 2, 1); |
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115 | kind = magic[1] - '1'; |
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116 | ascii = 1; |
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117 | if(kind >= 3) { |
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118 | ascii = 0; |
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119 | kind -= 3; |
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120 | } |
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121 | |||
122 | width = ReadNumber(src); |
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123 | height = ReadNumber(src); |
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124 | if(width <= 0 || height <= 0) |
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125 | ERROR("Unable to read image width and height"); |
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126 | |||
127 | if(kind != PBM) { |
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128 | maxval = ReadNumber(src); |
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129 | if(maxval <= 0 || maxval > 255) |
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130 | ERROR("unsupported PNM format"); |
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131 | } else |
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132 | maxval = 255; /* never scale PBMs */ |
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133 | |||
134 | /* binary PNM allows just a single character of whitespace after |
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135 | the last parameter, and we've already consumed it */ |
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136 | |||
137 | if(kind == PPM) { |
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138 | /* 24-bit surface in R,G,B byte order */ |
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139 | surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 24, |
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140 | #if SDL_BYTEORDER == SDL_LIL_ENDIAN |
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141 | 0x000000ff, 0x0000ff00, 0x00ff0000, |
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142 | #else |
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143 | 0x00ff0000, 0x0000ff00, 0x000000ff, |
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144 | #endif |
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145 | 0); |
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146 | } else { |
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147 | /* load PBM/PGM as 8-bit indexed images */ |
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148 | surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 8, |
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149 | 0, 0, 0, 0); |
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150 | } |
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151 | if ( surface == NULL ) |
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152 | ERROR("Out of memory"); |
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153 | bpl = width * surface->format->BytesPerPixel; |
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154 | if(kind == PGM) { |
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155 | SDL_Color *c = surface->format->palette->colors; |
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156 | int i; |
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157 | for(i = 0; i < 256; i++) |
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158 | c[i].r = c[i].g = c[i].b = i; |
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159 | surface->format->palette->ncolors = 256; |
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160 | } else if(kind == PBM) { |
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161 | /* for some reason PBM has 1=black, 0=white */ |
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162 | SDL_Color *c = surface->format->palette->colors; |
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163 | c[0].r = c[0].g = c[0].b = 255; |
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164 | c[1].r = c[1].g = c[1].b = 0; |
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165 | surface->format->palette->ncolors = 2; |
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166 | bpl = (width + 7) >> 3; |
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167 | buf = malloc(bpl); |
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168 | if(buf == NULL) |
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169 | ERROR("Out of memory"); |
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170 | } |
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171 | |||
172 | /* Read the image into the surface */ |
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173 | row = surface->pixels; |
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174 | for(y = 0; y < height; y++) { |
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175 | if(ascii) { |
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176 | int i; |
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177 | if(kind == PBM) { |
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178 | for(i = 0; i < width; i++) { |
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179 | Uint8 ch; |
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180 | do { |
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181 | if(!SDL_RWread(src, &ch, |
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182 | 1, 1)) |
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183 | ERROR("file truncated"); |
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184 | ch -= '0'; |
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185 | } while(ch > 1); |
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186 | row[i] = ch; |
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187 | } |
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188 | } else { |
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189 | for(i = 0; i < bpl; i++) { |
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190 | int c; |
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191 | c = ReadNumber(src); |
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192 | if(c < 0) |
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193 | ERROR("file truncated"); |
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194 | row[i] = c; |
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195 | } |
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196 | } |
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197 | } else { |
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198 | Uint8 *dst = (kind == PBM) ? buf : row; |
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199 | if(!SDL_RWread(src, dst, bpl, 1)) |
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200 | ERROR("file truncated"); |
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201 | if(kind == PBM) { |
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202 | /* expand bitmap to 8bpp */ |
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203 | int i; |
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204 | for(i = 0; i < width; i++) { |
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205 | int bit = 7 - (i & 7); |
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206 | row[i] = (buf[i >> 3] >> bit) & 1; |
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207 | } |
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208 | } |
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209 | } |
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210 | if(maxval < 255) { |
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211 | /* scale up to full dynamic range (slow) */ |
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212 | int i; |
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213 | for(i = 0; i < bpl; i++) |
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214 | row[i] = row[i] * 255 / maxval; |
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215 | } |
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216 | row += surface->pitch; |
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217 | } |
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218 | done: |
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219 | free(buf); |
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220 | if(error) { |
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221 | SDL_FreeSurface(surface); |
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222 | IMG_SetError(error); |
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223 | surface = NULL; |
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224 | } |
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225 | return(surface); |
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226 | } |
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227 | |||
228 | #else |
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229 | |||
230 | /* See if an image is contained in a data source */ |
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231 | int IMG_isPNM(SDL_RWops *src) |
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232 | { |
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233 | return(0); |
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234 | } |
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235 | |||
236 | /* Load a PNM type image from an SDL datasource */ |
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237 | SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
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238 | { |
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239 | return(NULL); |
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240 | } |
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241 | |||
242 | #endif /* LOAD_PNM */>>>>>>>>=>=>=>=> |